AVS 59th Annual International Symposium and Exhibition
    Surface Science Wednesday Sessions
       Session SS-WeA

Paper SS-WeA9
Glycolaldehyde as a Probe Molecule for Biomass-derivatives

Wednesday, October 31, 2012, 4:40 pm, Room 21

Session: Catalysis on Metals and Alloys
Presenter: W. Yu, University of Delaware
Authors: W. Yu, University of Delaware
M. Barteau, University of Delaware
J. Chen, University of Delaware
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Controlling the activity and selectivity of converting biomass-derivatives to syngas (H2 and CO) is critical for the utilization of biomass feedstocks as renewable sources for chemicals and fuels. One key chemistry in the conversion is the selective bond scission of the C-OH and C=O functionalities, which are present in many biomass-derivatives. Because of the high molecular weight and low vapor pressure, it is relatively difficult to perform fundamental surface science studies of C6 sugars, such as glucose and fructose, using ultrahigh vacuum (UHV) techniques. Glycolaldehyde (HOCH2CH=O) is the smallest molecule that contains both the C-OH and C=O functional groups, as well as the same C/O ratio as C6 sugars, and thus is selected as a probe molecule in the current study to determine how the presence of the C=O bond affects the reaction mechanism . Using a combination of density functional theory calculations and experimental measurements, our results indicate that the reaction pathway of glycolaldehyde to produce syngas can be enhanced by supporting monolayer Ni on a Pt substrate, which shows higher activity than either of the parent metals. Based on the comparison of the activity and reaction intermediates of ethylene glycol and glycolaldehyde, the presence of the C=O functionality enhances the activity on the Pt(111) surface. On the other hand, for surfaces with high activity toward the O-H bond scission, such as NiPtPt(111), the presence of C=O does not significantly affect the activity or reaction pathway of C2 oxygenates. Furthermore, the Pt substrate can be replaced by tungsten monocarbide (WC) to achieve similar activity and selectivity, indicating the possibility of using Ni/WC to replace Ni/Pt as active and selective catalysts with higher stability and lower cost.